1. Field of the Invention
The present invention relates to a video signal processing apparatus which performs a progressive conversion processing, or the like on a video signal in an interlaced system obtained from a source of a cinema film, and to an image display apparatus that installed such video signal processing apparatus.
2. Description of the Related Art
Units that are configured to detect whether a source of a video signal is a cinefilm or a video camera, and that have an IP conversion processing suitable for the source and a higher image quality display, are used in an IP converting portion that converts a video signal of an interlaced system (interlace format) to a progressive video signal (a video signal of a progressive format) in a television receiving apparatus or the like. Furthermore, recently, in case of a video signal with which a cinefilm becomes a source (hereinafter, also called a film signal), a smoother movement of an image is realized by implementing a frame rate conversion processing by motion compensation after the IP conversion processing, (for example, see Patent Document 1: Japanese Unexamined Patent Publication No. 2004-34333).
FIGS. 1 and 2 show a processing for detecting a film signal. Among these, FIG. 1 shows a processing for detecting a 2:2 film signal to which a 2:2 pulldown processing (conversion to a PAL signal (576i) of 50 Hz) was implemented. In the 2:2 film signal, two fields are formed from the same frame by separating one frame of film into odd field and even field. Then, if a difference of each field between the signal and the one field delayed signal is taken, a difference between the same frames and a difference between the different frames are calculated alternately, so the difference changes alternately as 0, 1, 0, 1 . . . , in case of motion picture, and consequently that it is the 2:2 film signal is detected.
FIG. 2 shows a processing for detecting a 3:2 film signal to which a 3:2 pulldown processing (conversion to a NTSC signal (480i) of 60 Hz) was implemented. In the 3:2 film signal, three fields are formed from the frame of the same film and subsequently, two fields are formed from the frame of the same film, and then these states are continued alternately. Then, if a difference between the signal and the two field delayed signal is taken, a difference between the same fields is calculated at every five fields and the difference becomes 0, and consequently that it is the 3:2 film signal is detected.
FIGS. 3A to 3C show a frame rate conversion processing by motion compensation as an example of the 2:2 film signal. After the 2:2 film signal (PAL signal (576i) of 50 Hz) as shown in FIG. 3A is converted a progressive signal of 25 Hz by an IP conversion processing (2:2 pulldown reverse processing) by which the odd field and even field as shown in FIG. 3B are added, a motion vector is detected at interval of one field, as shown in FIG. 3C, and the intermediate field is interpolated by the motion compensation, thereby converting the frame rate from 25 Hz to 50 Hz. The motion of the image that is displayed becomes smooth by the frame rate conversion.